When they were both in the Florida Legislature. It was probably also intended to be an investment, but they were not very good at handling their money if that was the intention!
While looking for the article on the foreclosure, I found this:
Could David Rivera cost Marco Rubio the vice presidency?
Posted by Chris Cillizza at 02:40 PM ET, 05/01/2012
Rivera is the very controversial Florida U.S. House member who remains under FBI and IRS investigation for a series of campaign finance irregularities that led Miami-Dade prosecutors to conclude recently that the Sunshine State Republican essentially live[d] off donations from campaign contributors for the better part of a decade. (Those prosecutors did not bring criminal charges against Rivera though its worth reading the full 16-page memo on their findings here.)
I think until David is federally cleared on any wrongdoing, it is damn near a [disqualifier]...we continually hear that though the state authorities took a pass, they did so knowing others would not, said one senior Republican operative in Florida. Marco is his friend, and he is loyal, but it comes to a point when stakes are so high and margins so close that it would be the difference between being invited to the ticket or not.
On Monday, Rubio was asked about Rivera by Fox News Channels Bret Baier and heres what he said:
Hes a friend. I mean, hes a friend Ive known on a personal level even before I was elected or he was elected to office. So look, I know hes going through a tough time. And weve all read the press reports and none of us like to see that about anybody, much less a friend. And hes going to have to deal with those issues.
More:
http://www.washingtonpost.com/blogs/the-fix/post/could-david-rivera-keep-marco-rubio-from-the-vice-presidency/2012/05/01/gIQAVYSauT_blog.html
There is more about the foreclosure in this article, written after the matter was settled. Rubio would have been another train wreck for Rmoney!